One or more of the starting points specified in the trace operation are located outside of the tier extent.
There is a Trace rule configured to generate the diagram. Among the network feature or network objects in input for the diagram generation, there are devices with terminals that are tied to different tiers and prevent the Trace rule from executing.
Starting points used in a trace operation must be inside the extent defined for the tier.
The diagram template related to the generated diagram must be reviewed. A Set Starting Point rule must be configured before the Trace rule to clearly specify the terminal or terminals that are expected as the starting points for the trace execution.